1. Field of the Invention
The present invention relates to photonic crystals, and more specifically to producing white light from photonic crystals.
2. Description of the Related Art
Photonic crystals (PC's) are materials, such as semiconductors, that prohibit the propagation of light within a frequency bandgap through an artificial periodicity in their refractive index. In two dimensional photonic crystals, a common way to achieve this artificial periodicity is to periodically arrange air holes (i.e., to have a lattice of air holes) in the material making up the photonic crystal (i.e., silicon or GaN).
Photonic crystals may also contain defects (or cavities). These are locations within a lattice of air holes where one or more air holes are not present. These defects may be created using photolithography techniques. Photonic crystals can be seen as an optical analogue of electronic crystals that exhibit bandgaps due to periodically changing electronic potentials. By introducing a defect within a PC, one or more highly localized electromagnetic modes may be supported within the bandgap (analogous to impurity states in solid state devices). These defects greatly modify the spontaneous emission of light from photonic crystals.